Electric motors are used in various household, office, automotive, and industrial applications. A typical electric motor includes a rotor surrounded by an electromagnet, called a stator. When varying electrical energy is applied to the stator, a magnetic field is generated that produces a torque on the rotor, spinning the rotor. The rotor includes an output shaft that connects to a device, such as a pump, fan, belt, or gear, to operate the device with the rotational output of the motor. A motor can also include electronic components configured to receive electrical energy and to vary the amount, frequency, and phase of the electric power delivered to the motor, controlling the torque generated in the rotor and the speed at which the rotor spins.
As a motor is operated, the components of the motor and the electronic control components generate heat. If a motor generates excessive heat, the motor components may degrade and the electronic components may be damaged. Typically, electric motors are ventilated to enable air to cool the components and reduce overheating. However, some electronic components may fragment upon failure, producing debris that can escape a motor in which electronic components are ventilated. In some applications, debris exiting the motor can cause issues outside the motor and damage to nearby components. Therefore, avoidance of overheating in electric motors and containment of debris from catastrophic failure of electronic components are beneficial goals of electric motor design.